Even though the principles that determine the effectiveness of detergents for household (or home) and professional (including institutional and industrial) laundries are similar, detergents for large-scale institutional or industrial use generally differ insofar as they must be designed to meet the special circumstances associated with laundry on an industrial scale and/or in an institutional context. Contrary to home laundry, professional laundries have to deal with large volumes of textile items and require therefore completely automatic processing with microprocessor-controlled machines and dosing units. The length of the washing process differs from that of home laundry and in some cases the washing is performed with soft water. Soil levels can be significantly higher in certain types of loads of professional laundry (restaurant linens for example) than in household laundry and the loads are considerably bigger. The composition of the loads is more uniform, in terms of both, types of fabrics and soils. Typically the same kinds of fabrics stained with the same kind of soils are washed together. For example a typical commercial laundry load will consist of only towels, only bed linen or only tablecloths and napkins.
Table linen (tablecloths and napkins) represents a heavy demand load for professional foodservice. The linen is soiled with difficult greasy stains. Large unique loads of these items are washed routinely together. Repeat loads of these items happen frequently with repeated re-use of the fabrics within the foodservice venue. Sometimes fabrics are pre-treated from the manufacture in order to facilitate soil removal, but it can wear off upon the numerous repeated re-use/rewash. The removal of stains can be more challenging in professional laundry than in the case of domestic laundry, especially in the professional foodservice sector.
The removal of food stains, especially on polyester and in particular on table linen in professional laundry has not been successfully solved. Several solutions have been proposed using soil release polymers. WO96/24657 discloses high alkalinity detergent composition comprising non-ionic surfactant and a soil release polymer. The composition is in powder form and it is delivered into the main wash of an institutional textile washing process. U.S. Pat. No. 6,200,351 relates to an institutional textile washing process in which a soil release polymer is used in a separate pre-treatment step.
The solutions proposed by the prior art involve harsh conditions (extremely high pH) and/or large amount of soil release polymer and/or a separate step to the washing process. One of the objectives of this invention is to provide a method of professional laundry which is gentle with the treated textiles and at the same time is economic and easy to implement.